there is no need for the warmup workaround anymore, dotnet/BenchmarkDotNet#1573 has solved the problem

Author: adamsitnik

src/benchmarks/micro/Serializers/Json_FromString.cs

@@ -13,33 +13,25 @@ namespace MicroBenchmarks.Serializers
     [GenericTypeArguments(typeof(CollectionsOfPrimitives))]
     public class Json_FromString<T>
     {
-        private readonly T value;
         private string serialized;
 
-        public Json_FromString() => value = DataGenerator.Generate<T>();
-
         [GlobalSetup(Target = nameof(Jil_))]
-        public void SerializeJil()
-        {
-            serialized = Jil.JSON.Serialize<T>(value, Jil.Options.ISO8601);
-
-            Jil_(); // workaround for https://github.com/dotnet/BenchmarkDotNet/issues/837
-        }
-
-        [GlobalSetup(Target = nameof(JsonNet_))]
-        public void SerializeJsonNet() => serialized = Newtonsoft.Json.JsonConvert.SerializeObject(value);
-
-        [GlobalSetup(Target = nameof(Utf8Json_))]
-        public void SerializeUtf8Json_() => serialized = Utf8Json.JsonSerializer.ToJsonString(value);
+        public void SetupJil() => serialized = Jil.JSON.Serialize<T>(DataGenerator.Generate<T>(), Jil.Options.ISO8601);
 
         [BenchmarkCategory(Categories.ThirdParty)]
         [Benchmark(Description = "Jil")]
         public T Jil_() => Jil.JSON.Deserialize<T>(serialized, Jil.Options.ISO8601);
 
+        [GlobalSetup(Target = nameof(JsonNet_))]
+        public void SerializeJsonNet() => serialized = Newtonsoft.Json.JsonConvert.SerializeObject(DataGenerator.Generate<T>());
+
         [BenchmarkCategory(Categories.Runtime, Categories.Libraries, Categories.ThirdParty)]
         [Benchmark(Description = "JSON.NET")]
         public T JsonNet_() => Newtonsoft.Json.JsonConvert.DeserializeObject<T>(serialized);
 
+        [GlobalSetup(Target = nameof(Utf8Json_))]
+        public void SerializeUtf8Json_() => serialized = Utf8Json.JsonSerializer.ToJsonString(DataGenerator.Generate<T>());
+
         [BenchmarkCategory(Categories.ThirdParty)]
         [Benchmark(Description = "Utf8Json")]
         public T Utf8Json_() => Utf8Json.JsonSerializer.Deserialize<T>(serialized);

src/benchmarks/micro/Serializers/Json_ToStream.cs

@@ -16,15 +16,16 @@ namespace MicroBenchmarks.Serializers
     [GenericTypeArguments(typeof(CollectionsOfPrimitives))]
     public class Json_ToStream<T>
     {
-        private readonly T value;
+        private T value;
 
-        private readonly MemoryStream memoryStream;
-        private readonly StreamWriter streamWriter;
+        private MemoryStream memoryStream;
+        private StreamWriter streamWriter;
 
         private DataContractJsonSerializer dataContractJsonSerializer;
         private Newtonsoft.Json.JsonSerializer newtonSoftJsonSerializer;
 
-        public Json_ToStream()
+        [GlobalSetup]
+        public void Setup()
         {
             value = DataGenerator.Generate<T>();
 
@@ -36,9 +37,6 @@ public Json_ToStream()
             newtonSoftJsonSerializer = new Newtonsoft.Json.JsonSerializer();
         }
 
-        [GlobalSetup(Target = nameof(Jil_))]
-        public void WarmupJil() => Jil_(); // workaround for https://github.com/dotnet/BenchmarkDotNet/issues/837
-
         [BenchmarkCategory(Categories.ThirdParty)]
         [Benchmark(Description = "Jil")]
         public void Jil_()

src/benchmarks/micro/Serializers/Json_ToString.cs

@@ -13,12 +13,10 @@ namespace MicroBenchmarks.Serializers
     [GenericTypeArguments(typeof(CollectionsOfPrimitives))]
     public class Json_ToString<T>
     {
-        private readonly T value;
+        private T value;
 
-        public Json_ToString() => value = DataGenerator.Generate<T>();
-
-        [GlobalSetup(Target = nameof(Jil_))]
-        public void WarmupJil() => Jil_(); // workaround for https://github.com/dotnet/BenchmarkDotNet/issues/837
+        [GlobalSetup]
+        public void Setup() => value = DataGenerator.Generate<T>();
 
         [BenchmarkCategory(Categories.ThirdParty)]
         [Benchmark(Description = "Jil")]

src/benchmarks/micro/runtime/PacketTracer/Render.cs

@@ -3,7 +3,6 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
-using System.Collections.Concurrent;
 using System.Runtime.Intrinsics;
 using System.Runtime.Intrinsics.X86;
 using BenchmarkDotNet.Attributes;
@@ -20,9 +19,6 @@ public class SoA
 
         private int[] rgbBuffer = new int[Width * 3 * Height]; // Each pixel has 3 fields (RGB)
 
-        [GlobalSetup]
-        public unsafe void Setup() => Render(); // run it once during the Setup to avoid https://github.com/dotnet/BenchmarkDotNet/issues/837s
-
         [Benchmark]
         public unsafe void Render()
         {

src/benchmarks/micro/runtime/perflab/BlockCopyPerf.cs

@@ -13,14 +13,10 @@ public class BlockCopyPerf
         private byte[] bytes;
 
         [Params(10, 100, 1000)]
-        public int numElements; 
+        public int numElements;
 
         [GlobalSetup]
-        public void Setup()
-        {
-            bytes = new byte[numElements * 2];
-            Buffer.BlockCopy(bytes, 0, bytes, numElements, numElements);
-        }
+        public void Setup() => bytes = new byte[numElements * 2];
 
         [Benchmark]
         public void CallBlockCopy() => Buffer.BlockCopy(bytes, 0, bytes, numElements, numElements);